Optical technologies play an increasingly prominent role in numerous applications, such as in medicine, research, communications, displays, media devices, computing systems, etc. An ongoing trend to miniaturize and integrate optical systems parallels miniaturization and integration that has occurred in electronics. Electrical devices have transitioned from a platform of vacuum tubes, to discrete transistors, and finally to integrated circuit chips in which transistor elements are integrated on a substrate of silicon or other suitable material. Similarly, there is an interest in integrated optical systems produced in/on substrates of silicon, glass, sapphire, silicon dioxide, indium phosphide (“InP”), or some other suitable material.
Such integrated optical systems could comprise lasing dies, optical modulators, optical attenuators, optical amplifiers, optical waveguides, and/or other optical elements and features that are attached to, embedded in, or otherwise integrated with a substrate that typically has at least one planar surface. Integrated optical systems may further comprise electronic logic elements, transistors, and/or other electrical devices that coexist on or in the substrate with optical devices. Optical channels, optical paths, or waveguides typically conduct optical signals with the integrated optical system. The channels may be embedded within the substrate, may be covered by a coating, may span through free space, or may comprise an air gap, for example. Oftentimes, the optical channels lack good accessible for testing, evaluation, or design confirmation conducted with conventional technologies. With the channels situated in inaccessible locations, an engineer or an automated testing machine can not readily determine the optical properties of the channels using conventional technologies. One conventional approach to studying optical channels involves modeling the optical system in software; however, determining the modeling parameters and confirming that the model is accurate can also be difficult with conventional technologies.
To address these representative deficiencies in the art, what is needed is an improved capability for evaluating optical devices, for determining how light flows through optical devices, and for identifying physical and optical parameters of optical devices. A further need exists for characterizing optical channels that are prohibitively small, covered, embedded, or otherwise essentially inaccessible to physical insertion of a detector into the channels. Yet another need exists for extracting luminous energy from an optical channel to support determining something about the channel or about some device associated with the channel. Still another need exists for a technology that can perform nondestructive testing or evaluation of optical systems, including optical systems that may comprise (or that may consist of) expanded beam elements, lenses, waveguides, optical fibers, gratings, filters, thin films, semiconductor elements, laser chips or dies, and/or detectors, for example. A technology filling one or more of these needs would facilitate more robust optical designs, shorter engineering cycles, more efficient manufacturing, improved theoretical and practical understanding of optical systems, failure analysis, optimizing of fabrication processes and parameters, and/or cost effective post-production inspection, among other benefits.